Performance evaluation of a location system guided transport vehicles based on the combination of UWB radio technology and a time reversal technique
In guided transport, the precise location of trains is vital for nominal operation of the transport system. In a propagation environment such as a railway line, an effective location sensor is complex to design and validate since it must operate in the presence of many fixed and mobile obstacles constituted by the infrastructure and the trains. In this thesis, to design such a sensor, we propose the use of so-called spectral diversity techniques also found under the name of Ultra Wideband radio (UWB). In this work, the latter is also associated with the Time Reversal (TR) technique to take advantage of the complex propagation environment. The objective is to obtain a reliable and robust location of rail vehicles by focusing UWB signals to antennas or ground trains. Theoretical studies combined with simulations were performed on the properties of energy focusing of TR technique taking into account several parameters related to antennal configurations, propagation channels and the railway environment. The contribution of TR on the accuracy of the positioning system was quantified by comparing the conventional UWB positioning system alone and then, combining it with TR. The theoretical results and simulations of the proposed solution have been validated by experiments carried out in an anechoic chamber and in indoor environment.